In Konqueror, use the → to toggle hidden files and folders on and off.
In Konqueror, click on the file and choose → from the menu that appears. A list of applications appears.
Select the default application you want for the file type. If the application is not on the list, use the Add button to add the application to the list.
Select the Remember application association for this type of file checkbox. Click Ok to apply your changes.
Using the program Krename, it is possible to rename multiple files according to a naming scheme which you define.
Install the Krename package from the Universe repository (see the section called “Managing Repositories”).
Launch Krename by choosing → →
To open rar files, install the unrar package from the Multiverse repository (see the section called “Managing Repositories”).
To open a rar file, double click on it.